Hand-held food products have been a regular part of the culture of man in every region of the world for thousands of years. From the egg rolls of China, burritos and enchiladas of Mexico and pizzas of the Greeks in 400 B.C., the popularity and consumption of these favorites has increased at a steady rate.
Traditional products have been assembled by hand. Food products have been hand placed on a wrap or shell and folded or rolled one at a time. In the modern factory production environment these practices have resulted in repetitive motion injuries to workers and significant workers compensation and medical expenses for employers.
With the advent of automated assembly equipment and food freezers, the need has developed to deposit food products onto wraps and shells at high rates of speed. Simple gravity depositors are suitable for low rates under 30 per minute. As assembly rates reach and exceed 250 per minute other means must be employed.
Complex methods and machines such as shown in U.S. Pat. Nos. 6,263,789, 6,303,135 and 6,558,720 have been employed to deposit food products onto wraps and shells. These have included numerous sensors for filling, encoders, and master controllers. Food products are extruded and then forced to undergo extreme changes in motor speed, even reversing direction, in response to position sensor inputs to master controllers. The radical changes in velocity and direction drastically limit the type of food products and require the product to be modified by temperature and pressure to form compressed chilled portions that can accept the physical forces imposed by methods and mechanisms of prior art.
It is an object of the present invention to eliminate the need for filling sensors. Positioned in close proximity to the filling, such sensors are costly and prone to interruption in operation due to deposits of the filling material they are intended to sense blocking the photoeyes. The blockage of the photoeyes leads to uncontrolled portions of food product and unacceptable deposit position. This creates rejected product and incurs downtime to identify and correct the source of the system malfunction. Meat product depositing equipment must be intensely cleaned. Washing with chemical solutions and high pressure sprays can easily damage sensitive photoeye components resulting in improper system operation, rejected product waste, and downtime to repair.
It is another object of this invention to eliminate the requirement for encoders, data medium, and controllers to monitor the position of wraps or shells and the position of food product segments. Prior art has utilized encoders to generate digital position information representing the location of shells, data medium to store the digital data and master controllers to calculate and direct conveyor motors to execute motion profiles to correct the position of filling segments that would otherwise be misplaced from the proper relationship to the shell. The encoders are complex electro-mechanical devices with a rotating shaft coupled to a moving belt with gears, belts or chains. The shaft seal is an entry point for high pressure water and corrosive chemicals in a meat production washdown equipment environment. Connectors on cables used to transmit encoder pulse information often corrode in a washdown environment and are costly and time consuming to replace. The master controllers receiving the encoders must be located in close proximity to the encoders and therefore electronic components and circuit boards are subjected to destructive humidity and chemical vapors, must be protected from the wash water sprays and the resulting sealed enclosures require air conditioning to remove the heat generated by the controllers which would otherwise destroy themselves.
By designing the effective length of the food product conveyor to equal the length of the food portion as taught by the present invention, there is no need for employment of correction distance such as that utilized in U.S. Pat. No. 6,263,789. According to the present invention, the new or replacement first edible food portion is placed directly behind the first edible food portion in process. As the portion in process leaves the food product conveyor, the new or replacement food portion is placed on the food product conveyor which then turns off until the next wrapper, shell or other second edible food portion is in position. By eliminating the correction distance, the portions of food product can be placed directly behind one another. This assures that any lack of space between the wraps or shells has no effect on the ability of the apparatus to properly deposit the food product. Prior art has used the correction distance method. This method cannot deposit on shells spaced closer than the fixed minimum distance required to correct the position of a filling segment as it travels towards the shell. This inability to deposit on directly adjacent shells results in the rejection and waste of the wrap and shell products.
Another object is to reduce or eliminate the damage to the first edible food product caused by relative motion. Relative motion is the differential velocity of the food product being pumped or otherwise deposited and the food product conveyor belt. This damage is most extreme when the blade of the food product cutter is operated or the food product pump stops after delivering its portion. In U.S. Pat. No. 6,263,789, the segment of food product is placed on the conveyor while the conveyor is in motion. When the cutter is operated, the food portion velocity goes to 0 fpm while the conveyor belt travels at full speed beneath the portion. Some specially formulated food products such as chilled shredded beef or chicken, compressed with the proper sauce to glue the filling segment together, can tolerate having the segment end stuck in a cutter blade while the belt slides underneath. Other common food products such as ground beef, vegetables, fruit, or mixtures of common burrito fillings such as eggs, beans, chopped vegetables and meat, break up and scatter across the food product belt, rendering the system of U.S. Pat. No. 6,263,789 completely unable to portion or position the food product. This factor establishes a small limited and closely defined range of food products that can be successfully deposited with this method.
The following patents and other patent documents are also known: U.S. Pat. No. 3,757,676, U.S. Pat. No. 3,858,497, U.S. Pat. No. 3,901,137, U.S. Pat. No. 3,946,656, U.S. Pat. No. 4,014,254, U.S. Pat. No. 4,047,478, U.S. Pat. No. 4,084,493, U.S. Pat. No. 4,112,834, U.S. Pat. No. 4,334,464, U.S. Pat. No. 4,388,059, U.S. Pat. No. 4,439,124, U.S. Pat. No. 4,457,225, U.S. Pat. No. 4,483,242, U.S. Pat. No. 4,516,487, U.S. Pat. No. 4,517,785, U.S. Pat. No. 4,608,919, U.S. Pat. No. 4,637,304, U.S. Pat. No. 4,691,627, U.S. Pat. No. 4,719,117, U.S. Pat. No. 4,913,043, U.S. Pat. No. 4,953,455, U.S. Pat. No. 5,101,957, U.S. Pat. No. 5,328,709, U.S. Pat. No. 5,330,776, U.S. Pat. No. 5,456,298, U.S. Pat. No. 5,509,350, U.S. Pat. No. 5,832,813, U.S. Pat. No. 5,912,035, U.S. Pat. No. 5,281,427, U.S. Pat. No. 5,814,360, U.S. Pat. No. 6,263,789, U.S. Pat. No. 6,303,165, U.S. Pat. No. 6,558,720, and Great Britain Patent document 2223391A.